This paper is part of a series of publications developed by the Latin America-Comet assay (LA-COMET) group, which emerged in 2021, during the Asociacion Latinoamericana de Mutagenesis, Carcinogenesis y Teratogenesis Ambiental Congress, to organize the LA-COMET initiative. A total of 104 alkaline comet assay publications in animal (aquatic and terrestrial) and plant models, authored by members of this group, were analyzed to determine how DNA damage under experimental and environmental exposure conditions is assessed. The manuscript reflects the broad use and versatility of the comet assay in diverse taxonomic groups (invertebrates and vertebrates), in vivo research models, and cell types (e.g., erythrocytes, branchia cells, retinal epithelial cells, peripheral blood, liver, kidney, lung, bone marrow, testicle and nasal cells). Application of the comet assay in diverse biological systems requires careful methodological standardization to ensure reproducibility and allow for comparability of results. In order to unify the evaluations of the papers, a quality score system was developed, the 'quality score comet assay' (QSca), providing values reflecting the methodological rigor of the execution of the assay. The group identified key elements when performing the comet assay and uses them as the focus for the QSca score. The LA-COMET initiative will provide opportunities to strengthen collaborative networks among Latin American countries, promoting more integrative and regionally connected research where the comet assay can be used as a reliable and reproducible tool for the assessment of DNA damage in diverse biological models.
The increasing application of nanotechnology has raised concerns regarding the genotoxic potential of engineered nanoparticles due to their unique physicochemical properties and biological interactions. The present study evaluated the genotoxic effects of four oxide nanoparticles-aluminium oxide (Al₂O₃NPs), iron oxide (Fe₃O₄NPs), silicon dioxide (SiO₂NPs), and titanium dioxide (TiO₂NPs)-in human peripheral blood cells using the alkaline comet and cytokinesis-block micronucleus (CBMN) assays. Sublethal concentrations were selected based on IC₅₀ values determined by a resazurin-based cell viability assay. The comet assay revealed a significant dose-dependent increase in DNA strand breaks for all nanoparticles, with TiO₂NPs inducing the highest levels of primary DNA damage, as reflected by the percentage of tail DNA. In contrast, SiO₂NPs produced the highest frequency of micronuclei in the CBMN assay, indicating pronounced chromosomal instability. Fe₃O₄NPs showed a significant increase in nucleoplasmic bridge formation at higher concentrations, while Al₂O₃NPs exhibited comparatively lower genotoxic effects. Overall, these findings demonstrate differential genotoxic responses among oxide nanoparticles, influenced by particle size and composition, and highlight their potential to induce genome instability even at sublethal exposure levels.
The repeated-dose liver micronucleus (RDLMN) assay is an in vivo genotoxicity test that is useful for detecting hepatocarcinogens and is anticipated to be incorporated into general toxicity studies. Although many RDLMN studies have been reported, further investigation is necessary to demonstrate age-related sensitivity and to evaluate compounds with cytostatic properties.In this study, a repeated oral dose study of 2,6-dinitrotoluene (2,6-DNT), a substance known to have cytostatic properties, was conducted in Crl:CD(SD) rats starting at 6 or 8 weeks of age for 28 days. Liver micronucleus (LMN) frequency, mitotic index (MI), and cell proliferation markers, Ki-67 and PCNA, were subsequently evaluated. As a result, LMN frequency increased significantly at all dose levels, showing a reverse dose-response relationship, and there were little differences between age groups. The number of Ki-67-positive cells increased in both age groups, and it was considered compensatory cell proliferation following toxicity at higher doses. Histopathological evaluation revealed prominent anisokaryosis, particularly at 8 weeks of age at start of dosing, and DNA content analysis confirmed that these cells were polyploid, suggesting endoreduplication.This study confirmed that LMN detection sensitivity in the RDLMN assay did not differ between rats aged 6 or 8 weeks at the start of dosing, and that micronucleus-inducing ability was detected even in compounds with cytostatic properties. For appropriate interpretation of the results, histopathological assessment, the analysis of cell proliferation markers and DNA content analysis are useful.
India's rapid population growth positively correlates with solid waste generation. Indiscriminate disposal in unsanitary landfills is dominant, and releases hazardous contaminants, that pose genotoxic risks to humans and biota. This study evaluated DNA damage and genome instability induced by solid waste emissions of Indian origin. Following PRISMA guidelines, 36 peer-reviewed studies published until 2025 were selected. These studies reported 40 bioindicators and 56 genotoxic biomarkers, with cell lines and comet assay most frequently reported. Significant DNA strand breaks, micronucleus formation, chromosomal aberrations, nuclear abnormalities, and sperm defects in exposed models were consistently reported, often in dose- and time-dependent patterns. Random-effects meta-analysis using pooled standardized mean differences showed significant positive effect sizes for micronucleus and comet endpoints (p ≤ 0.0001), confirming increased genetic damage in exposed groups. Although substantial heterogeneity was observed (I² = 95.73% for micronucleus; 87.66% for comet), the direction of effect remained consistently positive. Risk-of-bias assessment indicated overall moderate to high methodological quality, with common reporting gaps in exposure characterization and blinding procedures. Oxidative stress and ROS generation are dominant drivers of genome instability. Signaling pathways causing DNA adduct, DNA repair impairment, epigenetic dysregulation, and mitochondrial-mediated apoptosis were other mechanisms. Despite strong evidence of somatic and germline genotoxicity, epidemiological data and quantitative exposure assessments remain inadequate. Integrated exposure monitoring, advanced molecular and epigenetic biomarkers, dose-response characterization and long-term population-level biomonitoring are needed to strengthen causal inference and human health risk assessment. Emissions from solid waste facilities in India represent a credible genotoxic hazard warranting improved waste management, and regulatory enforcement.
On a global scale, the versatility and high sensitivity of the comet assay have promoted its use from different perspectives to determine genotoxic damage. With this in mind and through the formation of a Latin American group denominated "LA-COMET", a review of the manuscripts published by the group is proposed from the perspective of in vitro studies, using the alkaline comet assay. To facilitate the analysis of the 81 manuscripts published between 1996 and 2022, they were classified into four categories based on the type of agents evaluated by the assay: 1) environmental pollutants; 2) pesticides and their mixtures; 3) radiation and drugs; and 4) natural products. The objective of this review was to describe the strengths and versatility of in vitro studies reflected by cellular models, putative DNA damaging agents, and the use of specific enzymes to identify particular DNA lesions. In addition, an in vitro QS (quality score) was established, taking into consideration the data provided in the publications regarding the cellular model, the method of disaggregation and the cell suspension obtention. Other considerations included the clarity of the description of the treatments, the use of negative and positive reference controls, and the use of specific enzymes and/or the functional evaluation of DNA repair. The analysis demonstrated that the publications of the LA-COMET group of in vitro models exhibited a high score with respect to the important parameters established in the OECD agreements.
Technological and chemical advancements have heightened human exposure to synthetic and natural substances, necessitating precise toxicological assessments through sensitive biomarkers. The comet assay has emerged as a robust, minimally invasive tool for biomonitoring. This study reviews 64 articles published between 1997 and 2022 by the LA-COMET group—a collaborative network of 17 research teams across seven Latin American countries (Argentina, Bolivia, Brazil, Colombia, Mexico, Paraguay, and Uruguay).The analysis reveals that research primarily focuses on occupational and environmental exposures, specifically evaluating the impact of pesticides, heavy metals, organic solvents, and particulate matter. The assay proved highly effective in identifying genotoxic effects in exposed populations compared to reference groups, including vulnerable cohorts such as children, women, and patients with clinical conditions like breast cancer and malaria. To enhance future research rigor, this work utilizes and proposes standardized scoring systems, namely QSca (assay quality score) and hmQS (human monitoring quality score). Ultimately, this review underscores the comet assay’s pivotal role in characterizing regional health risks and seeks to establish evidence-based practices to inform public health policies in Latin America.
Cisplatin and its analogues are a cornerstone of cancer chemotherapy; however, their therapeutic potential is limited by severe side effects and the development of drug resistance. To address these issues, nanocarriers and/or platinum prodrugs are being evaluated. Previous in vitro studies showed that ultra-small (< 5 nm) iron oxide nanoparticles coated with tartaric and adipic acids (FeAT-NPs) are an efficient delivery system for the cisplatin prodrug cis-diamminetetrachloroplatinum(IV) (cisplatin(IV)). In this study, the in vivo behavior of cisplatin (IV) conjugated with the FeAT-NPs (FeAT-NPs-Pt(IV)) was evaluated using Drosophila melanogaster as a preliminary non-mammalian animal model. The resulting FeAT-NPs-Pt(IV) nanoconjugate was compared to free cisplatin and cisplatin(IV) regarding platinum incorporation into DNA, measured using inductively coupled plasma mass spectrometry (ICP-MS), as well as toxicity and genotoxicity, which were assessed using the alkaline comet and the w/w+ eye-spot SMART assays. Results revealed that the nanoconjugate achieved over eightfold higher DNA platination than free cisplatin, which is consistent with efficient cellular uptake and the subsequent intracellular release and activation of the prodrug. Despite this high platination, the nanoconjugate induced DNA strand-break levels similar to cisplatin and lower mutation and recombination frequencies than both cisplatin and cisplatin(IV), in both nucleotide excision repair (NER) efficient and deficient conditions. No significant toxicity was detected at the tested concentrations. These findings suggest that, in vivo, FeAT-NPs-Pt(IV) acts as an effective delivery system, potentially enabling the slow intracellular formation of active cisplatin. This would increase bioavailability to its target (DNA), while maintaining a significantly lower genotoxic stress profile compared to free cisplatin. Nonetheless, additional studies in tumor mammalian models are required to further explore these observations.
The in vitro micronucleus (IVMN) assay is a genetic toxicity assay routinely conducted in early drug development to evaluate clastogenicity and aneugenicity. At this discovery stage, synthetic routes for potential active pharmaceutical ingredients (API) are not optimized, which can lead to incomplete purification or solvation. API in genetic toxicity screens often contain residual solvent(s) in higher quantities than will be present in the GMP material. Understanding when solvents used either in API synthesis or as a vehicle may interfere with genetic toxicity screening results of APIs is important. In this work, twenty solvents commonly used in API synthesis were analyzed in the IVMN assay. These twenty solvents include acetonitrile, formic acid, anisole, dichloromethane, heptane, isopropyl amine, dimethyl sulfoxide, sodium hexafluorophosphate, N,N-Dimethylethylamine, N,N-Dimethylformamide, cyclopentyl methyl ether, 2-propanol, 1-butanol, 1-Methyl-2-pyrrolidinone, methanol, tetrahydrofuran, 2-Methyltetrahydrofuran, ethyl acetate, trifluoroacetic acid, and 2,6-Di-tert-butyl-4-methylphenol. When the in vitro data was correlated to available in vivo genotoxicity data published in the literature, only 5 of the 14 positively correlated. However, when a 10 mM limit of exposure was applied to the solvents, 13 of the 14 correlated to the in vivo literature results. While the results do not consider vehicle interaction within the assay, the data demonstrates that residual solvent carryover from API or other sources is generally not of concern. The 10 mM limit also reduces the false-positive risk of this assay. Baseline cytotoxicity and micronucleus formation from the solvents in this system provide a ranking on which solvents may produce confounding results in the assay.
The widespread use of benzalkonium chloride (BAC) as a disinfectant necessitates a thorough evaluation of its toxicity. This study investigated the cytotoxic and genotoxic effects of BAC, alongside its recovery potential, using the Allium cepa test system. Roots were exposed to 5, 15, and 30 mg/L BAC for 24 and 48 h. EC₅₀ values were initially determined by linear interpolation as 38.3 mg/L (24 h) and 28.0 mg/L (48 h); a supplementary four-parameter nonlinear regression (Hill sigmoid model) yielded 31.79 mg/L (95 % CI: 18.56-45.03; R² = 0.9993) and 27.66 mg/L (95 % CI: 19.87-35.44; R² = 0.9995), respectively, confirming the robustness of dose selection. Cytogenetic analysis revealed significant, dose-dependent decreases in mitotic index and alterations in mitotic phase distribution. BAC induced clastogenic and aneugenic effects, manifesting as significant increases in C-mitosis, anaphase bridges, chromosome breakages, and stickiness. Micronucleus formation was statistically significant only at 30 mg/L after 24 h (p = 0.521 at 48 h). Roots transferred to distilled water for recovery demonstrated persistent mitotic suppression and genomic instability, indicating that BAC inflicts irreversible damage exceeding cellular repair capacity. These findings establish that BAC possesses significant genotoxic and cytotoxic hazard potential for non-target eukaryotic organisms.
The diesel exhaust constituent 1-nitropyrene (1-NP) is classified as a probable human carcinogen and other constituents 1,8-dinitropyrene (1,8-DNP) and 3-nitrobenzanthrone (3-NBA) are classified as possible human carcinogens by the International Agency for Research on Cancer. These nitroarenes are activated by nitroreduction via nitroso- and hydroxylamino- intermediates on route to the corresponding amine product(s). Two types of DNA adduct can occur in this sequence. First, the hydroxylamino- intermediate can undergo sulphonation or acetylation giving rise to a strong leaving group so that stable covalent adducts can form. Second, back oxidation of these air sensitive intermediates can give rise to reactive oxygen species and nitrogen species (ROS, RNS) so that oxidatively damaged bases can form. Human aldo-keto reductases AKR1C1, AKR1C2 and AKR1C3 play prominent roles in the nitroreduction of these nitroarenes in human lung cell lines. We now report that when AKR1C1-AKR1C3 are transfected into V79-4 cells we observe a significant increase in HPRT gene mutation. The mutation is dependent on AKR1C enzyme activity since isoform specific inhibitors reduced the number of mutant colonies formed. ROS scavengers reduced the number of mutant colonies formed with 1-NP, 1-8-DNP and 3-NBA in the presence of transfected AKR1C1. Ethyl gallate and the superoxide dismutase mimetic (MnTBAP) reduced the number of mutant colonies formed. Nitric oxide scavengers, 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazoyl-1-oxy-3-oxide and uric acid, also reduced the number of mutant colonies formed. Our results suggest that both 8-oxo-dG and 8-nitro-dG lesions may contribute to the mutation observed. Since AKR1C1-AKR1C3 are potently induced by NRF2, its activation might increase the mutagenicity of nitroarenes in the context of diesel exhaust exposure.
OBJECTIVE:The liver micronucleus (MN) assay is useful for detecting genotoxic hepatocarcinogens that may be missed by the erythrocyte MN assay. Because micronuclei form only in dividing cells, evaluating hepatocyte proliferation is essential for interpreting negative results. This study assessed proliferating cell nuclear antigen (PCNA) as a proliferation marker in the repeated-dose liver MN (RDLMN) assay and compared its performance with Ki-67 and the mitotic index (MI). METHODS:This study was a retrospective analysis using archived liver tissues from two previously conducted studies. In the first, male Crl:CD(SD) rats aged 3.5-12 weeks were examined for age-related changes in hepatocyte proliferation. In the second, rats had been treated with N-nitrosodi-n-propylamine (NDPA), quinoline (QUN), or carbendazim (CBZ) to evaluate compound-related proliferative responses. Liver sections were immunostained for PCNA. In the compound-treated groups, previously unreported mitotic index (MI) data recorded during the original studies are presented here for the first time. Results were compared with previously reported Ki-67 labeling data obtained from the same animals. PCNA and Ki-67 were evaluated in 1000 hepatocytes per animal (n = 5), whereas MI was determined from 4000 hepatocytes because of the low mitotic frequency. Statistical analyses used Fisher's exact test and the Cochran-Armitage trend test. RESULTS:PCNA-positive hepatocytes declined markedly with age (approximately 57.0 % at 3.5 weeks to 5.8 % at 12 weeks). NDPA and QUN induced dose-dependent increases in PCNA labeling consistent with regenerative proliferation. In older rats, the very low baseline frequencies of MI and Ki-67 limited quantitative evaluation of proliferative status at necropsy. CONCLUSIONS:Hepatocyte proliferation decreased markedly with age in the RDLMN context. PCNA immunostaining provided a stable and quantifiable indicator of hepatocyte proliferative activity with higher detectable baseline labeling than MI and comparable interpretability to Ki-67 under the examined conditions. These findings suggest that PCNA may be useful for supporting interpretation of negative RDLMN assay results in a context-dependent manner, although further studies are warranted to clarify its applicability across broader experimental settings.
Despite recent advances in cancer treatment, classical chemotherapy is still used as first-line treatment for a variety of tumors. However, the side effects associated with it are a relevant problem and one of the main reasons for discontinuation of cancer treatment. In this sense, antioxidants are widely used to reduce the side effects associated with chemotherapy, but little is known about their possible antagonistic effects. Therefore, this study aims to investigate the modulation of cisplatin (CDDP) and 5-fluorouracil (5-FU) by ascorbic acid (AA) in mice transplanted with sarcoma 180. A solid tumor was induced in the axillary region of Swiss mice (Mus musculus) and treated with isolated CDDP or 5-FU (5mg/kg) or in combination with low-dose AA (3.5 mg/kg / 17.5 mg/kg). To determine treatment efficacy, hematological and biochemical markers, as well as tumor and organ size were measured. The comet assay was used to assess genotoxicity in femoral bone marrow cells. The results demonstrated that tumor reduction was lower in the animals treated with the combination of 5-FU/CDDP with AA than in the groups receiving only the drugs. The comet assay demonstrated that CDDP/5-FU in combination with AA greatly reduced genotoxicity in bone marrow cells. It is hypothesized that the modulating effect of AA is due to its antioxidant activity, which influences the efficacy of chemotherapeutic drugs. The results show that the AA intake in combination with conventional chemotherapy leads to reduced treatment efficacy in animal models, warranting further studies on nutritional supplementation for cancer patients.
Background Bacterial microbiome of the respiratory tract can influence the development of respiratory diseases, including lung cancer (LC). However, establishing a causal link between certain members of the respiratory microbiota and LC is challenging. This study aimed to analyze the sputum microbiome and its association with chromosome damage in leukocytes of LC patients and healthy controls. Methods Sputum samples from 150 LC patients and 104 healthy donors were analyzed by 16S rRNA gene sequencing. Chromosomal aberrations (CA) were assessed cytogenetically in lymphocytes. Bioinformatics analyses examined correlations between sputum microbiome profiles and chromosome damage. Results The sputum microbiomes of LC patients and healthy controls did not have significant indicators for the species richness index and the Faith’s phylogenetic diversity, whereas the comparison index in LC patients was significantly lower than that of healthy controls. Bacterial community structures (beta diversity) were also similar in patients and controls. We showed higher abundance of Bacillus, Prevotella, Granulicatella and Bergeyella in LC patients' sputum. LC patients exhibited increased aberrant metaphases, as well as all major CA types, compared to healthy subjects. Positive associations between aberrant metaphases and bacteria from Fusobacteria phylum, genera Bacteroidetes, Leptotrichia, Lactobacillus, Macellibacteroides, Mycoplasma, Lachnoanaerobaculum, Bulleidea, and Dialister were found in LC patients. In healthy donors, CA only correlated with Anaerorhabdus and Peptococcus. Streptobacillus and Zhouia positively correlated with the proportion of aberrant metaphases in both LC patients and in healthy individuals. Conclusions Specific bacterial genera in sputum associate with chromosomal damage in host cells, suggesting possible genotoxic potential of these bacteria.
Ionizing radiation is a potent genotoxic carcinogen. In this study, acute DNA damage-related biomarker responses were evaluated in peripheral blood lymphocytes of adults undergoing radiographic investigations for orthodontic treatment. Patients (n = 22) for orthodontic treatment were divided into two groups: Group 1 - conventional radiographs (Orthopantomogram (OPG), Lateral Cephalogram (LC) and two Intra-oral periapical radiographs); Group 2 - Cone Beam Computed Tomography (CBCT). Peripheral blood samples (3 mL) were collected before and after radiography imaging. Gamma-H2AX (γ-H2AX) focus formation, micronucleus (MN) formation, and ferredoxin reductase (FDXR) gene expression were evaluated as biomarkers of exposure and response. The frequency of γ-H2AX focus and micronuclei increased significantly (p < 0.05 and p < 0.001) from pre- and post-radiography in both groups. FDXR showed significant upregulation and downregulation in Groups 1 and 2, respectively indicating divergent early transcriptional response between the groups. Conventional radiographs and low-dose CBCT exerted acute DNA damage-related biomarker responses in adult orthodontic patients. FDXR gene showed greater upregulation with conventional radiographs than CBCT. Group 1 and group 2 post-radiography showed no statistical difference when assessed with the three biomarkers for acute damage. Future studies with larger samples and long-term follow-up are needed to validate the findings and provide a basis for safety recommendations.
Arsenic is a prevalent environmental contaminant recognized for its detrimental effects on several biological systems, particularly the male reproductive system. Although genotoxic effects linked to arsenite (As) exposure have been shown in various cell and tissue types, research concerning the male reproductive system is limited. In this study, the cytotoxic, apoptotic, and genotoxic effects of As exposure were evaluated using in vitro assays in TM3 Leydig cells, cells that play a critical role in testicular function. Leydig cells were exposed to increasing As concentrations (1, 2, 4, and 6 µM) for 24 h. Cell viability, oxidative stress (ROS production, SOD, CAT, GPx, and GSH levels), apoptosis (propidium iodide/Hoechst double fluorescent staining), and genotoxicity (micronucleus, comet, and chromosomal aberration tests) were analyzed. The administration of As markedly diminished cell viability in a concentration-dependent manner and inhibited antioxidant enzyme activity, resulting in a redox imbalance. An increase in the rate of apoptotic cells was noted in parallel to the As concentration. Genotoxicity analyses revealed an elevation in DNA damage, chromosomal aberrations, and micronucleus formation. In conclusion, As induces multifaceted toxic effects in TM3 Leydig cells by disrupting the oxidative balance, triggering apoptosis, and damaging genome integrity. This is the first in vitro study demonstrating genotoxicity of As in TM3 cells and offers an important contribution to the literature on male reproductive toxicity.
The DNA damage response (DDR) is crucial for maintaining genomic stability and preventing cancer development. Base excision repair (BER) and nucleotide excision repair (NER) play key roles in correcting oxidative and bulky DNA lesions, respectively. Alterations in these mechanisms have been implicated in breast and colorectal cancers (CRC), affecting both tumorigenesis and therapeutic responses. We have evaluated BER and NER activities in 85 cancer patients (58 breast cancer, 27 CRC) and 31 healthy controls. We used a comet assay-based approach to assess DNA repair capacity in peripheral blood lymphocytes. At diagnosis, patients exhibited lower BER and NER activities compared to controls, which suggests that impaired DNA repair mechanisms may contribute to cancer development. Following treatment, an overall increase in repair activity was observed, indicating cellular adaptation to therapy-induced DNA damage. This increase was greater in patients who later experienced relapse or metastasis, which suggests a possible link between enhanced repair capacity and treatment resistance. Our results also showed an interplay between BER and NER mechanisms, with their simultaneous activation potentially contributing to treatment resistance by enhancing tumour cell survival. These findings highlight the dual role of BER and NER in cancer progression and therapy outcomes, reinforcing their potential as biomarkers for predicting treatment response. Understanding the regulatory dynamics of these pathways may provide a foundation for improved personalized cancer treatment strategies.
This study assessed the water quality of the Capibaribe River, a major water resource in the state of Pernambuco, Northeastern Brazil. In vivo toxicogenetic analyses were conducted using the Comet assay in Drosophila melanogaster, together with physicochemical assessments at four sampling points along the river. Genotoxicity analyses revealed a progressive increase in DNA damage that corresponded to the degree of urbanization along the river. The lowest Damage Index (DI) was recorded at point P1, in the municipality of Paudalho (DI = 35.67), an environmental protection area. The highest DI levels were observed along the two most urbanized stretches of Recife (DI = 68.67), at points P3 and P4. At these sites, concentrations of Total Dissolved Solids (TDS), chloride, sulfate, phosphate, and nitrate exceeded the limits set by the Brazilian National Council for the Environment (CONAMA). Additionally, elevated levels of sulfur (S), aluminum (Al), potassium (K), sodium (Na), phosphorus (P), and magnesium (Mg), elements known to cause genetic damage, were also detected. These findings underscore the importance of assessing genotoxic effects in model organisms, particularly in the more urbanized stretch of the Capibaribe River. They also highlight the urgent need for pollution control measures, continuous monitoring, and the implementation of strict environmental policies to safeguard both human and environmental health.
The comet assay is a versatile tool for evaluating DNA damage; its use has spread worldwide, including in Latin America. The LA-COMET group is a Latin American collaborative network. In a bibliometric study, we have analyzed 246 publications from seven countries, particularly with regard to topics addressed and impact. Quality scores (QSca) were assigned, based on the technical performance of the alkaline comet assay. Most (60 %) of the publications were scored with QSca 60 points out of 63 or better. Among the most common topics of interest are cancer, in vivo assays, DNA damage, pollution, and gene expression. We highlight the wide range of research topics, categorized into a) human monitoring studies; b) in vitro studies; and c) studies in animal and plant models. The LA-COMET group is encouraging collaborations, both within and beyond the group, to address topics of interest in genetic toxicology.
The increasing dissemination of microplastics (MPs) in the environment and their potential adverse effects on human and animal health have raised significant concerns in the scientific community. In this context, we aimed to investigate the toxicity induced by polyethylene (PE) MPs in the blood of Swiss mice (Mus musculus), focusing on biomarkers of oxidative and nitrosative stress and genotoxicity. Thirty mice were distributed across three experimental groups: two groups intravenously inoculated with polyethylene MPs at target systemic blood concentrations of 7.1 µg/mL and 355 µg/mL, respectively, and a non-exposed control group. After five days of intravenous (single) exposure to MPs, analyses revealed particles in the blood, liver, and kidneys, indicating selective retention in these tissues. While the Comet assay demonstrated increased DNA damage in peripheral blood, corroborating the genotoxicity of MPs, biochemical analyses revealed a complex response that depended on the organ and the biomarker evaluated. In the liver, we observed a significant reduction in the oxidative stress index, a metric that integrates pro-oxidant parameters (ROS and MDA) in relation to the endogenous antioxidant activities of SOD and CAT. At the same time, in the kidneys, there was an increase in the ratio between SOD and CAT activity. In both organs, increased nitrite production suggests the induction of marked nitrosative stress. On the other hand, in the liver, MDA levels surprisingly decreased, suggesting that MPs may interfere with lipid peroxidation pathways or promote the diversion of ROS toward NO-mediated peroxynitrite formation, reducing classical lipid oxidative damage. Principal Component Analysis (PCA) and cluster analysis provided an exploratory and integrative overview of the dataset, revealing distinct biochemical patterns between the control and MP-exposed groups, with higher MP concentrations associated with more pronounced oxidative and genotoxic responses. Thus, we conclude that exposure to MPs can cause significant cellular damage, reinforcing the need for further research to understand the risks associated with MP contamination and to develop effective mitigation strategies.
Type 1 diabetes (T1DM), an autoimmune disease, is the result of damage to pancreatic beta cells, and causes prolonged hyperglycaemia. In males, diabetic hyperglycaemia can perturb sperm morphology and motility, reduce semen volume, and lower fertility. We have investigated the protective effects of dimethyl itaconate (DMI) on diabetes-induced germ cell damage in male SD rats. Diabetes was induced with streptozotocin and animals with blood glucose levels ≥ 250 mg/dL were included in the study. DMI was administered orally for four weeks. Testicular damage was evaluated by examining morphology, oxidative stress, inflammation, and hormonal levels. Diabetes increased oxidative stress (elevated MDA, reduced GSH levels), decreased sperm count and motility, and increased abnormal sperm morphology and fragmented sperm DNA. It also altered the expressions of key proteins in rat testes, including increased 8-OHdG, Caspase-3, p-NF-κB p65 and IL-6, and decreased 3β-HSD, Nrf2, HO-1 and SOD-1. DMI treatment significantly ameliorated these effects, demonstrating its protective role against diabetes-induced germ cell damage in rats.
